[all-commits] [llvm/llvm-project] 3d27b5: [EarlyIfConversion] Avoid producing selects with i...

[Jon Roelofs via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 3d27b5d28aabf8516aa1fefc78a6878b89a992f0
      https://github.com/llvm/llvm-project/commit/3d27b5d28aabf8516aa1fefc78a6878b89a992f0
  Author: Jon Roelofs <jonathan_roelofs at apple.com>
  Date:   2021-04-30 (Fri, 30 Apr 2021)

  Changed paths:
    M llvm/lib/CodeGen/EarlyIfConversion.cpp
    A llvm/test/CodeGen/AArch64/early-ifcvt-same-value.mir

  Log Message:
  -----------
  [EarlyIfConversion] Avoid producing selects with identical operands

This extends the early-ifcvt pass to avoid a few more cases where the resulting
select instructions would have matching operands.  Additionally, we now use TII
to determine "sameness" of the operands so that as TII gets smarter, so too
will ifcvt.

The attached test case was bugpoint-reduced down from CINT2000/252.eon in the
test-suite. See: https://clang.godbolt.org/z/WvnrcrGEn

Differential Revision: https://reviews.llvm.org/D101508